We theoretically investigate temporal cloaking (TC) in a Sagnac interferometer using conductivity-dependent cross-Kerr nonlinearity (CKN). By altering the phase and strength of conductivity, we observe changes in the effectiveness of TC, variations in relativistic group velocities (RGV), and shifts in the group index. The group index attains values up to [Formula: see text] depending on the phase angles [Formula: see text]. Similarly, the window of temporal gaps increases as a function of [Formula: see text] and the phase of conductivity, with higher conductivity strengths. The maximum temporal gap is [Formula: see text][Formula: see text]s. These results will contribute to advancement in secure quantum communication and precision rotation sensing technologies.
We theoretically investigate temporal cloaking (TC) in a Sagnac interferometer using conductivity-dependent cross-Kerr nonlinearity (CKN). By altering the phase and strength of conductivity, we observe changes in the effectiveness of TC, variations in relativistic group velocities (RGV), and shifts in the group index. The group index attains values up to [Formula: see text] depending on the phase angles [Formula: see text]. Similarly, the window of temporal gaps increases as a function of [Formula: see text] and the phase of conductivity, with higher conductivity strengths. The maximum temporal gap is [Formula: see text][Formula: see text]s. These results will contribute to advancement in secure quantum communication and precision rotation sensing technologies.
Abstract We theoretically explore the impact of cross-Kerr nonlinearity (CKN) on rotary photon drag (RPD) and temporal cloaking in a Sagnac interferometer. With the activation of CKN, significant improvements in RPD and temporal cloaking are observed. Drag angles of ± 1 × 10 − 3 and ± 5 × 10 − 3 radians are attained, similarly, temporal gaps of 10 μ s, 12 μ s and 13 μ s are observed. In addition to the observed electromagnetically induced transparency window, the group refractive index is drastically enhanced, time delay/advance are tuned from pico-radians to micro-radians, and reduced relativistic group velocities are achieved by activating CKN within the system. Additionally, the transmission pulses intensities are observed to be reduced with the dragging phenomenon. The findings may have potential applications in controlled image coding, rotation sensing and secure communication technologies.
Abstract The phenomenon of temporal cloaking (TC) via Raman gain is explored using Sagnac interferometer (SI) and atomic medium coupling. As a function of the pump field detuning, the temporal gap extends from 6 ms to 20 ms, with the presence of Raman gain in the system. Whereas, with variations in the control field phase angle, a temporal gap of 10 ms is achieved within the system. Similarly, the time delay/advance reaches to ±2 ms and ±5 ms. Additionally, positive and negative improved group refractive index is observed accompanied by negative and positive relativistic group velocities. The presented results may find applications in secure communication, image coding/design, and secure rotation sensing technologies.
Abstract We present a theoretical investigation of the photon drag by incorporating self-Kerr nonlinearity (SKN) in a Sagnac interferometer featuring a four-level atomic system. By introducing SKN in the system, we demonstrate significant improvements in the photon drag angles, ranging from ±10 micro-radians to ±1 centi-radians. Additionally, the presence of SKN leads to electromagnetically induced transparency (EIT), reduced group velocities, and a positive group index enhancement within the system. Conversely, in the absence of SKN, a negative group index is observed, accompanied by larger group velocities and minimal photon drag angles. The results obtained may have potential applications in various fields, such as slow-light detection, controlled image coding/design, efficient light modulators, and phase-matching in Brillouin scattering.
Abstract We theoretically demonstrate the impact of conductivity-dependent Raman gain (RG) on rotary photon drag (RPD) in a Sagnac interferometer (SI). The presence of conductivity-dependent Raman gain results in enhanced RPD angles, ranging from θ d = ± 0.56 radians to θ d = ± 0.7 radians. The susceptibility, group index, relativistic group velocities, and RPD exhibit significant fluctuations with changes in the conductivity phase. Specifically, we observe gain-singlets when the control field is deactivated, while gain doublets are achieved when the control field is activated. Moreover, within the gain regions, we observe normal dispersion, whereas anomalous dispersion is observed around the gain regions. These findings have potential applications in controlled image coding/design, four-wave mixing, photo detectors, light modulation, and phase-matching in Brillouin scattering.
The ability to interferometrically detect inertial rotations via the Sagnac effect has been a strong stimulus for the development of atom interferometry because of the potential 1010 enhancement of the rotational phase shift in comparison to optical Sagnac gyroscopes. Here we analyze ballistic transport of matter waves in a one-dimensional chain of N coherently coupled quantum rings in the presence of a rotation of angular frequency $\ensuremath{\Omega}$. We show that the transmission probability, T, exhibits zero transmission stop gaps as a function of the rotation rate interspersed with regions of rapidly oscillating finite transmission. With increasing N, the transition from zero transmission to the oscillatory regime becomes an increasingly sharp function of $\ensuremath{\Omega}$ with a slope $\ensuremath{\partial}T/\ensuremath{\partial}\ensuremath{\Omega}\ensuremath{\sim}{N}^{2}$. The steepness of this slope dramatically enhances the response to rotations in comparison to conventional single ring interferometers such as the Mach-Zehnder interferometer and leads to a phase sensitivity well below the quantum shot-noise limit typical of atom interferometers.
Quantum information processing with geometric features of quantum states may provide promising noise-resilient schemes for quantum metrology. In this work, we theoretically explore phase-space geometric Sagnac interferometers with trapped atomic clocks for rotation sensing, which could be intrinsically robust to certain decoherence noises and reach high precision. With the wave guide provided by sweeping ring traps, we give criteria under which the well-known Sagnac phase is a pure or unconventional geometric phase with respect to the phase space. Furthermore, corresponding schemes for geometric Sagnac interferometers with designed sweeping angular velocity and interrogation time are presented, and the experimental feasibility is also discussed. Such geometric Sagnac interferometers are capable of saturating the ultimate precision limit given by the quantum Cram\'er-Rao bound.